I have a 100+ year old house with base board of a similar look. I ended up making my own using three different cuts in conjunction with one another. I used rounded bit to achieve the inner radius, removed some of the material I think with the table saw (might have been a straight router bit) and then the top radius with the third cut. I little sanding evened all the surfaces. I made enough for several large rooms in my restoration project.
I believe you can have custom bits made, but I didn't want to spend the money when I could utilize the relatively simple existing bits I had. Good luck.